1. Fielf of the Invention
This invention relates to a method for desulfurizing molten iron using the dust collected at the time of smelting manganese or chromium which has previously been discarded as a waste, but the components of which have been found effective for desulfurization of molten iron.
2. Description of the Prior Art
Heretofore, alkali metal compounds such as soda ash or sodium hydroxide, and alkaline earth metals such as magnesium or their compounds such as calcium cyanamide or calcium carbide have been used as desulfurizing agents for molten iron. Methods for using these desulfurizing agents include, for example, a method in which the desulfurizing agent is placed beforehand in a ladle, and then molten iron is poured into the ladle, a method in which a shaking ladle is used in order to promote mixing a method in which an impeller is used for stirring, or an injection method in which the desulfurizing agent is blown into the molten iron together with an inert gas.
Because of its low cost and the simplicity of its use, soda ash has been regarded as the most feasible desulfurizing agent and has in fact been used in the largest amount, but since the desulfurizing effect of soda ash varies soda ash exhibits only a weak action in desulfurization when molten iron having a relatively low sulfur content is poured into a ladle.